Novel TUBB1 Mutation In Chinese Population Of 289 Patients With Congenital Hypothyroidism And Thyroid Dysgenesis

Objective: To study the types and characteristics of TUBB1 mutation in children with congenital hypothyroidism(CH)and thyroid dysgenesis(TD)in Shandong,China.In order to expand the pathogenic gene spectrum of TD and improve the quality of births for TD children consequently reducing the national and social burden,functional studies were used to explore the relationship between CH and the novel TUBB1 mutation and furtherly revealed the possible pathogenic mechanism.Methods: Mutation of the whole coding region of TUBB1 was analyzed by Sanger sequencing in 289 children with CH and TD from China.Biological information analysis of variant was performed.The functional studies were furtherly used to identify the effect of novel mutation on thyroid cells.Wild type and mutant eukaryotic expression vectors of TUBB1 were constructed.The RNA and proteins,extracted from Nthyori 3.1 cells after transfected by plasmid,were used for qRT-PCR and Western Blot to identify the effect of mutation on the TUBB1 expression of thyroid cells.In addition,cell proliferation test(CCK-8)and scratch test were used to detect the effect of mutation on the proliferation and migration of thyroid cells.Results: Among 289 children with CH and TD,4(1.4%)were found to have a c.952C>T(p.R318W)heterozygous mutation in TUBB1,resulting in the change of tryptophan into arginine at codon 318 of TUBB1 protein.Functional studies indicated that p.R318 W mutant decreased the mRNA and protein levels of TUBB1 and inhibited cell proliferation in human thyroid cell line.Conclusions: A novel heterozygous missense mutation of TUBB1 in children with CH and TD was identified firstly in China,laying the foundation for expanding the genotype-phenotype spectum of TD.However,since the mutation rate of TUBB1 is low in Shandong province,the pathogenesis of TUBB1 remains to be further studied.